System, method, and computer program for conditioning a building environment based on occupancy estimates

ABSTRACT

The present disclosure provides a system, method, and computer program for conditioning a building environment based on occupancy estimates. In one embodiment, the method includes tracking the user&#39;s entries to and exits from the building on a mobile device associated with the user for each of a plurality of users. Entry and exit event data from the users&#39; mobile devices are used to estimate occupancy of the building. The conditioning of the building environment is adjusted in accordance with changes in occupancy estimates. In certain embodiments, where the building has a plurality of zones, each entry and exit event may be correlated with one of the plurality of zones. Occupancy is estimated within each zone using the zone-correlated entry and exit events. Alternately, users&#39; locations within the building may be estimated using an indoor localization technique. Each zone is then conditioned in accordance with the occupancy of the zone.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to building conditioning managementsystems and, more specifically, to a system and method for conditioninga building environment based on occupancy estimates.

2. Description of the Background Art

Most buildings today operate on schedules. For example, the building'sheating, ventilation, and air-conditioning (HVAC) system may turn on atsix o'clock every weekday morning to an “occupied mode” (i.e., as if thebuilding were fully occupied) and turn off at seven o'clock everyweekday evening to an “unoccupied mode.” Rigid scheduling of thebuilding conditioning management systems is problematic because duringthe occupied mode, the building is often less than fully occupiedresulting in the inefficient use of energy and substantial unnecessarycosts and during the unoccupied mode, many occupants may still bepresent due to shifting work hours, project deadlines, company events,etc.

Therefore, there is a need for a system and method for more efficientlyconditioning a building environment based on occupancy estimates. Thiswould include tailoring the schedule based on real-time occupancy dataor historical occupancy patterns and outputting the conditioning levelbased on the number of people in a given space.

SUMMARY OF THE DISCLOSURE

The present disclosure relates to a system, method, and computer programfor conditioning a building environment based on occupancy estimates. Inone embodiment of the invention, the method includes tracking the user'sentries to and exits from the building on a mobile device associatedwith the user for each of a plurality of users. Entry and exit eventdata from the users' mobile devices are used to estimate occupancy ofthe building. The conditioning of the building environment is adjustedin accordance with changes in occupancy estimates.

In certain embodiments, where the building has a plurality of zones, themethod includes tracking the user's entries to and exits from thebuilding on a mobile device associated with the user for each of aplurality of users. Each entry and exit event may be correlated with oneof the plurality of zones. Occupancy is estimated within each zone usingthe zone-correlated entry and exit events. Each zone is conditioned inaccordance with the occupancy of the zone. In alternate embodiments, themethod includes estimating the user's location within the building usingan indoor localization technique for each of a plurality of users. Foreach of the users, one or more zones associated with the estimatedlocation of the user are identified. The occupancy of each zone isestimated based on the estimated locations of the users. Each zone isconditioned in accordance with the occupancy of the zone.

In certain embodiments, the occupancy of the building (or zones) isestimated continuously or periodically throughout a period of time andthe conditioning of the building/zones is adjusted during the period oftime in response to one or more threshold changes in the occupancyestimates. The conditioning of the building environment (or zones) mayinclude at least one of: (i) heating the building/zones, (ii) coolingthe building/zones, (iii) ventilating the building/zones, and (iv)lighting the building/zones.

In certain embodiments, each user is associated with a primary zonespecified by the user and, in response to receiving notice of an entryevent for a user, correlating the entry event with the user's primaryzone. In certain embodiments, correlating each entry/exit event with azone includes, for at least one entry/exit event, mapping a calendarevent in a user's calendar to a zone. In certain embodiments, the indoorlocalization technique includes using measurements related to signalstransmitted between the user's mobile device and a plurality of fixedsignal transmitters to estimate the user's location (e.g., using aGlobal Positioning System (GPS), WiFi, or Bluetooth beacons, etc.).

In certain embodiments, the occupancy is estimated at a first time and asecond time and the building (or zones) is conditioned at the first timebased on the occupancy estimate for the first time and at the secondtime based on the occupancy estimate for the second time.

In certain embodiments, the building includes an HVAC system and theadjusting step includes monitoring the estimated occupancy to determinewhether the estimated occupancy falls below or rises above apredetermined threshold. In response to the estimated occupancy risingabove the predetermined threshold, the HVAC system may be transitionedfrom a first mode of operation to a second mode of operation, where thesecond mode of operation has a higher energy consumption than the firstmode of operation. In response to the estimated occupancy falling belowthe predetermined threshold, the HVAC system may be transitioned fromthe second mode of operation to the first mode of operation.

In certain embodiments, estimating occupancy of the building includessetting a geofence around the building. Each of the plurality of users'mobile devices is then tracked when the mobile device enters or exitsthe geofence. The total number of entry/exit events may be aggregated todetermine a minimum number of users in the building. The minimum numbermay be multiplied by a deployment penetration factor, where thedeployment penetration factor is derived from an estimate of thepercentage of users in the building that have mobile phones that trackand report when the user enters or exits a geofence.

In certain embodiments, the method includes tracking the user's entriesto and exits from the building on a mobile device associated with theuser for each of a plurality of users. Occupancy of the building isdetermined as a function of time. Occupancy pattern data is createdbased on the occupancy as a function of time. The building environmentis conditioned based on the occupancy pattern data.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart that illustrates a method, according to oneembodiment, for conditioning a building environment based on theoccupancy of an entire building.

FIG. 2 is a flowchart that illustrates a method, according to oneembodiment, for conditioning individual zones based on the occupancywithin the zones.

FIGS. 3A-3B are flowcharts that illustrate a method, according to oneembodiment, for associating an entry event with a zone when the systemhas access to a user's calendar data.

FIG. 4 is a flowchart that illustrates an alternate method, according toone embodiment, for conditioning individual zones based on the occupancywithin the zones.

FIG. 5 is a flowchart that illustrates a method, according to oneembodiment, for creating occupancy pattern data and using occupancypatterns to condition a building.

FIG. 6 is a flowchart that illustrates a method, according to oneembodiment, for estimating occupancy.

FIG. 7 is a block diagram representation of a building conditioningmanagement system that can be used to implement certain embodiments ofthe invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present disclosure relates to a system, method, and computer programfor conditioning a building environment or zones within a building basedon occupancy estimates. As used herein, conditioning of the buildingenvironment or zones within the building includes at least one of: (i)heating the building/zones, (ii) cooling the building/zones, (iii)ventilating the building/zones, and (iv) lighting the building/zones,among other things that help to make a building environment morecomfortable for its occupants. In a preferred embodiment, the heating,cooling, and ventilating is performed by a centrally-controlled HVACsystem. The HVAC system may have an “occupied” mode and an “unoccupied”mode. The occupied mode is a higher-energy consumption mode (i.e., anincrease in heating/cooling and ventilation) intended for when thebuilding is above a certain occupancy threshold (e.g., during businesshours). Conversely, the unoccupied mode is a lower-energy consumptionmode (i.e., a decrease in heating/cooling and ventilation as compared towhen the building is above the threshold) (e.g., at night or onweekends).

FIG. 7 illustrates a building conditioning management system accordingto one embodiment of the invention. The system includes a clientapplication 715 running on a plurality of mobile devices 710. The clientapplication 715 tracks user entries to and exits from the buildingand/or user location within a building. The client application 715communicates with building conditioning management software 720 runningon a management server 730 to notify the software 720 of a user's entryand exit events relative to a building and/or a user's location withinthe building. The building conditioning management software 720estimates the occupancy of the building and/or zones within the buildingto determine how to condition the building. The management server 730communicates with and directs a HVAC system 740, which operates tocondition the building. The management server 730 may also control otherconditioning systems, such as building lighting systems.

FIGS. 1-6, and the corresponding description, set forth various methodsfor conditioning a building. The methods of FIGS. 1-6 may be implementedin other systems, and the invention is not necessarily limited to thesystem illustrated in FIG. 7. As a person skilled in the art wouldunderstand, the building conditioning management system may beconstructed in any number of ways within the scope of the presentinvention.

In one embodiment, as seen in FIG. 1, a building environment isconditioned based on the occupancy of the entire building. The clientapplication on the users' phones track the users' entries to and exitsfrom a building (step 110). The users may be people that are associatedwith the building (e.g., people who work in the building). The clientapplications report entry/exit events to a server that manages abuilding's conditioning settings (step 120). The events may be reportedin real-time or substantially real-time.

The server aggregates entry/exit reports and continuously orperiodically estimates occupancy of the building (step 130). In certainembodiments, the occupancy of the building is continuously tracked insubstantially real-time as entry/exit events are reported by the mobiledevices. In other embodiments, the occupancy of the building iscalculated on a periodic basis (e.g., every 15 minutes). In certainembodiments, the server may estimate occupancy more frequently duringcertain time periods (e.g., between 8:00 AM and 6:00 PM). In certainembodiments, the occupancy estimates are also based at least in part onhistorical entry/exit pattern data.

The system then conditions the building environment according to theoccupancy of the building (step 140). In one embodiment, the servermonitors estimated occupancy to determine if the occupancy is above orbelow a predetermined threshold. The predetermined threshold may be inpercentages of the building's occupants (e.g., above 5%) or in absolutenumbers (e.g., one person or greater). The threshold may bedifferentiated based on groups or class. For example, the threshold maybe 5% of the developers or technicians and 1% of the managers. If theestimated occupancy rises above the threshold, the HVAC system is set tothe occupied mode. If it falls below the threshold, the HVAC system isswitched to the unoccupied mode.

In certain embodiments, the system may be adaptive and/or predictive andmay switch to an occupied mode a predetermined period of time before theexpected occupancy. For example, if it takes the HVAC system about 45minutes to heat/cool/or ventilate a space in order to reach its setpoint, the building conditioning management system may transition theHVAC system from the unoccupied mode to the occupied mode 45 minutesprior to the expected occupancy.

In certain embodiments, the server may monitor for multiple occupancythresholds, and there may be multiple modes of operation for the HVACsystem, where as occupancy increases, the amount of conditioning(heating, cooling, ventilation) increases. This is particularly the casewith regard to ventilation. In certain embodiments, there may be onethreshold for heating and cooling and multiple thresholds forventilation. In some embodiments, ventilation may be increased graduallyor substantially linearly as a function of occupancy.

In another embodiment, as seen in FIG. 2, the system estimates occupancyon a per zone basis. The system tracks the users' entries to and exitsfrom a building on the users' mobile devices (step 210), and each entryand exit event is then associated with one of a plurality of zones(e.g., one zone per floor) in the building (step 220). In oneembodiment, each user is associated with a primary zone. A user, via theclient application, may be prompted to specify his primary zone when heenters the building or the user's primary zone may be part of the user'sprofile. Typically, a user's primary zone would include his officelocation, but it may also include all common areas to which he hasaccess. In this embodiment, when a user enters the building, the user'sentry event is associated with the user's primary zone.

In a further embodiment, the system has access to a user's calendar andis able to obtain calendar events that are associated with a time andlocation. Each location is mapped to a zone. If a calendar eventindicates a user is likely to be in another zone during a certain timeperiod, then the user will be temporarily associated with the other zoneduring the time period. See FIG. 3 for an example embodiment in whichthe system uses calendar data to associate a user with a zone.

The system estimates occupancy within each zone using zone-correlatedentry and exit data (step 230). When a user enters the building, theoccupancy of the zone associated with the user is incremented by one.When a user exits a building, the occupancy of the zone last associatedwith the user is decremented by one. If the system has calendar access,the zone occupancy is incremented and decremented as applicable at thestart and end of a calendar event.

Each zone environment is then conditioned in accordance with theoccupancy of the zone (step 240). For example, the HVAC system's settingfor each zone is adjusted based on the occupancy of the zone. In oneembodiment, the system switches the zone to an occupied mode when atleast one user is in the zone. In certain embodiments, the system, on aper-zone level, re-computes the minimum required airflow values as afunction of estimated occupancy. If system has access to calendar data,the system may preemptively condition a conference room in which ameeting is scheduled to take place based on the estimated number ofparticipants (e.g., the number of participants who have respondedaffirmatively to the calendar event). Likewise, the system may notcondition the participants' offices when they are in a meeting outsidetheir offices. In certain embodiments, the occupancy of the zones areestimated continuously or periodically throughout a period of time and,for each zone, the conditioning of the zone is adjusted during theperiod of time in response to one or more threshold changes in theoccupancy estimates for the zone.

FIGS. 3A-3B illustrate a method, according to one embodiment, forassociating an entry event with a zone when the system has access to auser's calendar data. The system receives an entry event for a user(i.e., the client application alerts the server that the user hasentered the building) (step 310). The user's primary zone is identifiedand the occupancy of the user's primary zone is incremented by one (step320). While the user is in the building, the system monitors whether anycalendar events are occurring for the user (step 330). Monitoring forcalendar events may be performed by the client application or by theserver depending on the configuration of the calendaring system. Ifthere is a calendar event occurring for the user, the zone associatedwith the calendar event (or the “calendar zone”) is identified (step340). The system then determines whether the calendar zone is differentfrom the user's primary zone (step 350). If the calendar zone is thesame as the user's primary zone, the system returns to step 330. If thecalendar zone is different from the user's primary zone, then the systemdecrements occupancy of the primary zone by one and increments occupancyof the calendar zone by one (step 360). When the calendar event hasfinished, the system decrements the occupancy of the calendar zone byone and increments the occupancy of the primary zone by one (if the useris still in the building) (steps 370 and 380). The system then returnsto step 330. If at any time during the process of FIG. 3, the userleaves the building, the occupancy of the zone last associated with theuser is decremented by one and the process ends for the user.

In an alternate embodiment of the invention, a user's mobile device isused to estimate a user's location within the building using an indoorlocalization technique. FIG. 4 illustrates an example of thisembodiment. For each registered user within a building, the user'slocation within the building is estimated by using signal measurementsfor signals transmitted between the user's mobile device and a pluralityof fixed signal transmitters (e.g., WiFi access points, Bluetoothbeacons, etc.) (step 410). In one embodiment, step 410 uses aradio-frequency (RF) localization technique to estimate a user'sposition. There are several RF localization techniques. Classicaltechniques involve measuring time-distance of arrival (TDOA) and angleof arrival (AOA), where a receiver estimates the distance between thereceiver and the sender by measuring the time taken for a RF wavefrontto travel from the sender to the receiver and back (TDOA), and the anglefrom which it came (AOA). These are among the most robust techniques butthey require specialized hardware with high-precision clocks andhigh-frequency signal processing (since light travels at roughly 1ft/ns, clock rates must be of the same order to achieve good accuracy).For this reason, these techniques are typically used in high-endapplications.

Alternatively, signal-strength based localization may be used toestimate a user's position within a building. Most commodity radiohardware (e.g., Wi-Fi cards, Bluetooth transceivers, etc.) provides somemeasurement of the signal strength at the receiver (typically in theform of the Received Signal-Strength (RSSI) metric). Localization usingthis technique often relies on assuming that the signal power level atthe transmitter declines according to a power law and then modeling thedecline using an RF fading model (Rayleigh or Rican models are popularchoices). By listening to multiple senders, a receiver can triangulatetheir positions. The effectiveness of signal-strength based localizationdepends on the indoor environment (e.g., amount interference from othertransmitters and paths for RF propagation).

Another indoor localization technique is to examine a set of nearbytransmitters to create a “fingerprint,” and corresponding thatfingerprint with a location. In some sense, this is simply applying alow-pass filter to a fading model and only using the informationcorresponding to whether or not each transmitter can be “heard.” Whenused with low-power transmitters like Bluetooth, whose range is onlytens of meters, combined with high-density environments (i.e., havingmany transmitters), this technique can result in good accuracy (althoughvariations due to deployment densities and propagation environments arestill inevitable).

Those skilled in the art will appreciate that other indoor localizationmethods may be used to estimate a user's location within the building.For example, enabled Bluetooth beacons may be used to allow a user toconfigure his phone to recognize when the phone is near his computer andto only indicate that his office is occupied when the phone is near thecomputer. In another example, phones equipped with high-sensitivity GPSreceivers may be used to identify a user's location within a building.

Indoor localization can be improved with user feedback. If users entertheir location (into the client application) at a particular time, thesystem can use the entered location to learn the relationship betweenthe signal transmitters (e.g., WiFi access points) and locations in thebuilding.

Once a location estimate for the user has been obtained, one or morezones associated with the estimated location are identified (step 420).If a localization method is not precise enough to place a user within aparticular zone, a “weighting” may be applied that would indicate thatall the zones that the user could be in are “occupied.” This is due tothe fact that many indoor localization techniques provide a probabilitydensity estimate for the location of the user rather than a single point(although the density estimate may be summarized into a singlemaximum-likelihood estimate). If a density estimate is available, thesystem may use that instead of a point estimate for the user's locationin order to avoid the possibility of under-ventilating. This couldhappen in several ways. In a conservative strategy, the system simplyassumes that any zone in which there is a non-negligible probability ofthe occupant being there is occupied as if the occupant were, in fact,there. This results in over-ventilation when the location estimate isbad, but nearly guarantees that any zone the user is in will have theappropriate ventilation.

In an alternate strategy, the probability density estimate is used tocompute the probability the user is in any particular zone. Forinstance, there might be a 40% chance the user is in zone A and a 60%chance the user is in zone B. The system then allocates the ventilationthat the user requires proportionally between the two zones (i.e., if 15CFM per user is required, zone A receives 6 CFM and zone B receives 9CFM). In this case, the system delivers exactly the requiredventilation, although it may be somewhat misdirected. This strategy isconsistent with certain building codes that do not require that theventilation be delivered to the zone in which the user is located aslong as it is delivered to somewhere in the building.

The system estimates occupancy of each zone based on the estimatedlocations of registered users (step 430). The user's location may beestimated continuously, periodically, at designated times, or on demand.Similar to previous method, this method may be used in conjunction withcalendar data, where, based on calendar data, the system maypreemptively condition a zone. For example, the system may preemptivelycondition a conference room in which a meeting is scheduled to takeplace based on the estimated number of participants (e.g., the number ofparticipants who have responded affirmatively to the calendar event).Likewise, the system may not condition the participants' office whenthey are in a meeting outside their offices. Each zone is conditionedbased on the occupancy of the zone (step 440). In certain embodiments,the occupancy of the zones are estimated continuously or periodicallythroughout a period of time and, for each zone, the conditioning of thezone is adjusted during the period of time in response to one or morethreshold changes in the occupancy estimates for the zone.

In another embodiment, as seen in FIG. 5, occupancy pattern data iscreated and used to condition a building. The system tracks entries toand exits from a building by mobile devices of a plurality of users(step 510). The events are associated with a time stamp. As discussedabove, in one embodiment, the client application tracks the user'sentries to and exits from a building and reports the events to theserver. The entry and exit events are aggregated according to time (step520). The occupancy of the building is determined as a function of time(step 530). The system creates occupancy pattern data based on theoccupancy estimates as a function of time (step 540). For example, theoccupancy pattern data may indicate that the building has an occupancyof n1 at 6:00 AM, n2 at 7:00 AM, n3 at 8:00 AM, etc. Recent occupancyestimates for a time period may be weighted more heavily than olderestimates. The building environment is then conditioned based onhistorical occupancy patterns (e.g., on a given day or time) (step 550).The entry and exit data may be associated with a zone and steps 530-550may be performed for each zone to enable the building to be conditionedon a zone-by-zone basis.

FIG. 6 illustrates an example method for estimating occupancy of abuilding. A geofence, which is a virtual perimeter, is set around abuilding (step 610). The client applications on users' mobile devicestrack when a user enters or exits the geofence (step 620). The mobilephone fires an alert when a user enters or exits the geofence (an entryor exit event). The phone logs each event in association with the timethe event occurred. Client applications report entry/exit events to themanagement server (step 630). The management server aggregates the totalnumber of entry/exit events to determine the minimum number of people inthe building (step 640). The management server multiples the minimumnumber by a deployment penetration factor (DPF) that reflects anestimate of the percentage of people in the building that have theclient application installed (step 650). The DPF may be derived from (i)the number of people who have the client application installed and (ii)the maximum occupancy estimates for the building or other data about thenumber of people who might be in the building at the time.

In other words, the DPF is simply an estimate of what fraction of peopleuse the mobile application on a regular basis, relative to thebuilding's population. Obtaining a count of active users may be obtainedby observing logs from the server. Estimating the total number of peoplein the building may be obtained from card-badge data, maximum codeoccupancy, or many other sources. The DPF is simply the quotient ofthese numbers and all occupancy estimates are to be increasedproportional to 1/DPF. For example, if only 20% of occupants provideregular data, the minimum number calculated in step 640 is multiplied by5 to get the estimated occupancy of the building.

Each entry/exit event may be associated with a zone, and steps 640 and650 may be performed for each zone. Steps 640 and 650 may be done inreal-time to determine a real-time, current occupancy of the building(as described in FIG. 1), or they may be performed over data aggregatedover a period of time (as described in FIG. 5).

The methods described with respect to FIGS. 1-6 are embodied in softwareand performed by a computer system (comprising one or more computingdevices) executing the software. A person skilled in the art wouldunderstand that a computer system has a memory or other physical,computer-readable storage medium for storing software instructions andone or more processors for executing the software instructions.

As will be understood by those familiar with the art, the invention maybe embodied in other specific forms without departing from the spirit oressential characteristics thereof. Accordingly, the disclosure of thepresent invention is intended to be illustrative, but not limiting, ofthe scope of the invention, which is set forth in the following claims.

The invention claimed is:
 1. A method, performed by a computer system,for conditioning a building environment based on occupancy estimates,wherein the building has a plurality of zones, the method comprising:for each of a plurality of users, tracking the user's entries to andexits from the building on a mobile device associated with the user; inresponse to receiving notice of an entry event for the user, associatingthe user with a primary zone specified by the user; monitoring theuser's calendar for calendar events occurring for the user; in responseto a calendar event occurring for the user at a location different fromthe user's primary zone, (i) temporarily associating the user with thezone associated with the calendar event and temporarily disassociatingthe user from the user's primary zone at the start of the calendar eventand (ii) disassociating the user from the zone associated with thecalendar event and re-associating the user with the user's primary zoneat the end of the calendar event; in response to receiving notice of anexit event for the user, disassociating the user from the zone lastassociated with the user; estimating occupancy within each zone usingthe zone-correlated entry, exit, and calendar events; and conditioningeach zone in accordance with the estimated occupancy of the zone.
 2. Themethod of claim 1, wherein the occupancy of the zones are estimatedcontinuously or periodically throughout a period of time and, for eachzone, the conditioning of the zone is adjusted during the period of timein response to one or more threshold changes in the occupancy estimatesfor the zone.
 3. The method of claim 2, wherein the occupancy withineach zone is estimated more frequently during certain time periods. 4.The method of claim 1, wherein conditioning of the zone comprises atleast one of: (i) heating the zone, (ii) cooling the zone, (iii)ventilating the zone, and (iv) lighting the zone.
 5. The method of claim4, wherein the occupancy within each zone is monitored for multiplethresholds, one or more thresholds being associated with (i) heating thezone, (ii) cooling the zone, (iii) ventilating the zone, and (iv)lighting the zone.
 6. The method of claim 1, wherein each of theplurality of users is associated with one or more of a plurality ofgroups and wherein the occupancy within each zone is monitored formultiple thresholds, each threshold corresponding to a group.
 7. Anon-transitory, computer-readable medium comprising a computer programthat, when executed by a computer system, enables the computer system toperform the following method for conditioning a building environmentbased on occupancy estimates, wherein the building has a plurality ofzones, the method comprising: for each of a plurality of users, trackingthe user's entries to and exits from the building on a mobile deviceassociated with the user; in response to receiving notice of an entryevent for the user, associating the user with a primary zone specifiedby the user; monitoring the user's calendar for calendar eventsoccurring for the user; in response to a calendar event occurring forthe user at a location different from the user's primary zone, (i)temporarily associating the user with the zone associated with thecalendar event and temporarily disassociating the user from the user'sprimary zone at the start of the calendar event and (ii) disassociatingthe user from the zone associated with the calendar event andre-associating the user with the user's primary zone at the end of thecalendar event; in response to receiving notice of an exit event for theuser, disassociating the user from the zone last associated with theuser; estimating occupancy within each zone using the zone-correlatedentry, exit, and calendar events; and conditioning each zone inaccordance with the estimated occupancy of the zone.
 8. Thenon-transitory, computer-readable medium of claim 7, wherein theoccupancy of the zones are estimated continuously or periodicallythroughout a period of time and, for each zone, the conditioning of thezone is adjusted during the period of time in response to one or morethreshold changes in the occupancy estimates for the zone.
 9. Thenon-transitory, computer-readable medium of claim 8, wherein theoccupancy within each zone is estimated more frequently during certaintime periods.
 10. The non-transitory, computer-readable medium of claim7, wherein conditioning of the zone comprises at least one of: (i)heating the zone, (ii) cooling the zone, (iii) ventilating the zone, and(iv) lighting the zone.
 11. The non-transitory, computer-readable mediumof claim 10, wherein the occupancy within each zone is monitored formultiple thresholds, one or more thresholds being associated with (i)heating the zone, (ii) cooling the zone, (iii) ventilating the zone, and(iv) lighting the zone.
 12. The non-transitory, computer-readable mediumof claim 7, wherein each of the plurality of users is associated withone or more of a plurality of groups and wherein the occupancy withineach zone is monitored for multiple thresholds, each thresholdcorresponding to a group.